CHARACTERIZATION OF THE LIPOPHILICITY OF FLUOROCARBON DERIVATIVES CONTAINING HALOGENS OR HYDROCARBON BLOCKS

The lipophilicity of highly lipophilic fluorochemicals containing halo gens or hydrocarbon blocks has been assessed using a new critical solu tion temperature (CST) method based on n-bromoalkanes. Measurements of CST are made as a function of n-bromoalkane chain length and extrapol ated to n-bromohexane for reference. The CST values using n-bromohexan e as the reference are much higher than those observed for n-hexane, t hereby moving the CST for lipophilic fluorochemicals into a measurable temperature range. The new method correlates well with both CSThex va lues and olive oil solubilities. The relative lipophilicities of vario us classes of highly lipophilic fluorochemicals are delineated, and a group additivity scheme for estimating CSTBrhex values is elucidated.